Electronic shelf edge price display system

ABSTRACT

A system for electronically displaying prices on shelves. To improve operational reliability and to reduce the field strengths emitted, the invention teaches that the transmitter elements are laid in the vicinity of the display units on the edges of the shelves, that the components of the display units receive the energy emitted by the transmitter elements inductively, and that the control transmitter sends an alternating current to the transmitter elements in the pauses between the data packets, and recharges the power supplies of the display units.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a system for the electronicdisplay of prices on shelves, with a computer, a control transmitterconnected to the computer and electronic display units fastened to theedges of the shelves, whereby at least the shelves equipped with displayunits are provided with electrically conducting transmitter elementswhich are fed an alternating current by the control transmitter and emitelectromagnetic energy, whereby the control transmitter, by means of thetransmitter elements, transmits to the display units data packets whichcontain the data to be displayed and are separated from one another intime by pauses, and whereby in each of the respective display unitsthere is a component to receive the energy emitted by the transmitterelements. This component feeds a charging current to a rechargeablepower supply. The power supply provides at least a portion of theoperating current of the display unit.

2. Background Information

In the field of modern retailing, the increasing use of bar codes toidentify the type and the price of products has resulted in thediminished use of individual price tags or stickers on each item ofmerchandise. To indicate the price of an item, a tag or label is usuallyaffixed to the edge of the shelf on which the item is located.

However, there is generally no guarantee that the price on the label isthe same as the price stored in the store computer which is used tocharge the customer at the checkout. This can lead to customercomplaints and possible legal action against the retailer. Moreover,when prices change, the replacement of the tags or labels on the shelfedges can generally be relatively labor-intensive, since each tag orlabel must essentially be prepared and replaced manually.

Accordingly, electronic price display signs have been developed whichcan be affixed instead of the conventional signs to the edge of theshelf, and which optically indicate the price of the merchandise andperhaps additional information. Since the electronic display units areconnected to the store computer, it can generally be guaranteed that theprice displayed on the sign is the same as the price which will becharged at the checkout. The central computer can also easily update theinformation on the respective display unit. This updating is usuallydone by means of a transmission which includes the specific address codefor the respective display unit or the respective group of displayunits, as well as the price information for the merchandise in question.In this manner, it is possible to modify the indicated prices, such asfor a special sale with reduced prices, with little expense or effort.

U.S. Pat. No. 4,500,800 discloses such electronic display systems whichare physically connected by wires to a power source and to the storecomputer. One disadvantage of these systems is that the hard-wiredconnection is cumbersome if the tags must be moved frequently.Furthermore, the contacts between the display tags and the connectingwires are subject to wear and tear, which results in errors in thetransmission of data and/or energy to the signs.

A generic system of this type is disclosed in Federal Republic ofGermany Patent No. 37 31 852 A1, which corresponds to U.S. Pat. No.4,821,291. To eliminate the hard wiring of the display units, thedisplay units are powered with electrical energy by means of internalbatteries. The information to be displayed is transmitted byelectromagnetic waves which are emitted by the control transmitterconnected to the central computer by means of wires laid above theshelves. The data are transferred in packets--corresponding to thedisplay units to be updated--and between the data packets there arepauses during which no waves are emitted. As an alternative tobatteries, the power supply for the display units can be in the form ofstorage batteries or capacitors of sufficiently high capacity, which arerecharged during the transmission of the data packets by means of theelectromagnetic energy received. In the generic system, the displayunits are also recharged with electromagnetic energy by a separatetransmitter outside operating hours.

The primary disadvantage of such a system is the inefficiency of thetransmission of energy to the display units. Since the wires used as thetransmission elements are laid on the top of the shelves and are alsoshielded by the shelves, it is generally necessary to use acorrespondingly high transmitter power to recharge the power source andfor the error-free transmission of data, to achieve sufficiently highfield strengths in the relatively distant display units. Thisessentially means that, on one hand, complex technical measures and highenergy levels are required, and on the other hand, that other electronicdevices (such as scales or cash registers) located in the vicinity couldbe affected by induced voltages. In addition, recharging is generallyonly possible during the transmission of the data packets, which furtherincreases the field strengths which must be emitted. Store personnel andcustomers can also be exposed to the effects of relatively intensiveelectromagnetic fields. If the recharging process is performed beforeand after business hours, on the other hand, large and expensive storagebatteries and capacitors with a high charge capacity are generallynecessary to guarantee the operation of the display units throughoutbusiness hours.

OBJECT OF THE INVENTION

The object of the invention is to create a reliable system for theelectronic display of prices on shelves, a system characterized bysubstantially error-free and efficient transmission of energy and datato the display units. The object of the invention is also to realize asystem which has both the flexibility of display units connected to thecomputer using wireless technology, as well as the reliability ofdisplays powered by hard-wired connections.

SUMMARY OF THE INVENTION

The invention teaches that the object can be achieved, in accordancewith at least one preferred embodiment, by installing the transmitterelements in the vicinity of the display units on the edges of theshelves, by having the components of the display units receive theenergy emitted by the transmitter elements inductively, and by havingthe control transmitter send an alternating current to the transmitterelements in the pauses between the data packets, to recharge the powersupplies of the display units. Preferably, such recharging can takeplace during the pauses between data packets.

The basic idea of the invention is, on the one hand, to install thetransmitter elements powered by the control transmitter in the immediatevicinity of the display units on the edges of the shelves, so that anefficient inductive energy transmission is possible. On account of theelimination of the antennas tuned to the transmission frequency, theinductive energy transmission is also economically realizable. On theother hand, the idea is to take advantage of the pauses between the datapackets to recharge the power sources of the display units. Since thecontrol transmitter sends an alternating current to the transmitterelements installed on the front side of the shelves in the pausesbetween the data packets, on account of the magnetic field whichsurrounds the transmitter element and which varies as a function of timeaccording to Faraday's law, a voltage is induced in the component of thedisplay element designed to receive the emitted energy (a coil, as arule), which is rectified and used to recharge the power source. Thepower source feeds the display unit with the operating current requiredfor the operation of the display proper and of the other electroniccomponents.

The advantages of the invention are that the display units can each beinstalled essentially in any desired position, independent of the datato be displayed, without requiring the time-consuming laying of agalvanic connection with the store computer. The frequent replacement ofthe internal batteries of conventional displays not powered byhard-wired connections can also be eliminated; and the maintenance costsare also lower than for known systems. The decisive factor, however, isthat on account of the short distance between the transmitter elementand the display unit, the inductive transmission of energy and theutilization of the pauses between data packets to recharge the powersupply, it is possible to use a significantly lower transmitter powerthan in known systems which operate with electromagnetic waves, tomaintain a charge in the power supplies and to supply the display unitwith electric current. On account of the significantly higher efficiencyof the energy transmission, there is thus essentially no need to fearany negative impact of the transmitter element on the environment in theform of electromagnetic waves. On account of the lower transmitterpower, the control transmitter can also be significantly smaller and bemanufactured significantly more economically. Finally, it is possible touse, as transmitter elements, any wires for conventional display unitswhich may already be present on the edges of the shelves, so thatessentially all that is necessary is the replacement of the displayunits.

Preferably, the data packets are transmitted inductively from thecentral store computer via the control transmitter and the transmitterelements on account of the optimal security of transmission (there isessentially no reason to fear interference or shielding) to a coil orsimilar device contained in the display elements, although anelectromagnetic or capacitive data transmission would also beconceivable.

Storage batteries and/or capacitors of sufficiently high capacity canpreferably be used as the rechargeable power supply for the displayunit. The storage batteries and/or capacitors are appropriately selectedso that at least the contents of the memory in the display units can beheld in memory for a period of several days, even after thedisconnection or failure of the control transmitter.

In the context of the invention, various possibilities exist to rechargethe power supply during the data transmission phase.

On one hand, the invention recommends, in one preferred embodimentthereof, that the energy emitted during the transmission of data by thetransmitter elements is also received inductively and used to rechargethe power supply, to further increase the efficiency of the energytransmission.

On the other hand, the invention teaches that the control transmittercan alternately switch back and forth in alternation between a datatransmission phase and a recharging phase, so that there is essentiallyno reason to fear any adverse effect on the fail-safe nature of thesystem (which is highly desirable for its optimal operation) on accountof the alternating currents in the transmitter elements used forrecharging. The display units essentially recognize the respectivephases on the basis of the induced voltages and switch internally fromone to the other.

In the concrete case, the alternating current flowing through thetransmitter elements in the pauses between the data packets, i.e. duringthe recharging phase, tends to have a constant frequency and amplitude.The result is that the recognition of the recharging phase by thedisplay elements is facilitated, and on account of the constantparameters of the induced voltages, an efficient, low-loss sizing andregulation of the recharging current of the power supplies easilybecomes possible. It would also be conceivable, however, to vary theamplitude and frequency of the alternating current (or the duration ofthe recharging phases) as a function of the level of the charge of thepower supplies, if the display units emit a status signal to the controltransmitter concerning their operating voltage. It is also possible tovary the duration of the charging phase, as a function of the level ofcharge in the display units.

To make possible an inductive transmission of data to the display unitsaccording to Faraday's law, it is also appropriate to have the controltransmitter modulate the data packets on an alternating current ofconstant frequency and amplitude which can be used as a carrier.Frequency modulation is thereby preferred, because it is significantlyless sensitive to external factors than amplitude modulation.Theoretically, it is also possible to superimpose the data on analternating current.

To distinguish between the data transmission phase and the recharging ofthe power supplies in the display units, the invention recommends, in atleast one preferred embodiment thereof, that the control transmittertransmit alternating currents of different amplitude and/or frequency inalternation to the transmitter elements (corresponding to the respectivephase). In the display units, the distinction between the two phases canbe made easily on the basis of the frequency or amplitude of the inducedvoltages. The advantage, in particular for a differentiation on thebasis of frequency, is that there is essentially no reason to fearinterference by the recharging phases with the transmission of data.

The display units can also send an acknowledgment to the computer afterreceipt of the data packets addressed to them. A corresponding datapacket is preferably converted by means of an inductance contained inthe display unit into a magnetic field which varies as a function oftime, and which induces a voltage in the adjacent transmitter elementwhich is transmitted to the computer by the control transmitter. It isapparent that, during the acknowledgment phase, essentially neither acharging of the power supplies nor a data transmission from the controltransmitter to the display unit can take place, since it wouldessentially not be possible to correctly receive the relatively weakacknowledgment signals.

There are also various possibilities for the concrete design of thecomponent of the display units used for reception. To reduce themanufacturing costs and the amount of space required, the inventionteaches, on the one hand, that the display units can preferably beequipped with only one component (i.e. one coil), which is used toreceive both the data and the recharging currents. On the other hand, itis also possible to divide the tasks between two separate components,each of which can easily perform its specific function.

An appropriate component for reception of the energy emitted by thetransmitter elements is a flat coil wound in layers.

Various embodiments of the transmitter elements are also conceivable inthe context of the invention. For example, they can be single-conductoror multiple-conductor cables, or can be in the form of a ribbon cable.To protect the transmitter elements against damage and to facilitatetheir installation, it is also appropriate to shape, possibly even moldor embed, the transmitter elements into a profile which forms the edgeof the shelf.

The magnetic field strengths in the display units can be increased if atleast the portions of the transmitter elements adjacent to the displaysare laid in the form of loops. The advantageous result is an increase inthe voltages induced and an improvement, in particular in the securityof data transmission.

The data to be transmitted to the shelf edge display units and opticallydisplayed by the display units are stored in a central computer whichcan be located, for example, in the main office of a retail chain, andwhich can preferably transmit the data via telephone lines or othersuitable devices to the computers in the individual stores. But thecomputer in the main office can also be eliminated, if the data arestored in the individual store computers. In the context of theinvention, the term "computer" is used to include all electronic datastorage and processing devices, e.g. including an EPOS (Electronic Pointof Sale) or similar devices.

The data are preferably transmitted by any desired combination of theabove-referenced computer systems by means of one or more controltransmitter. The control transmitter can be hard-wired to thetransmitter elements. Alternatively, the data can also be transmittedfrom the computer to the control transmitter and/or from the controltransmitter to intermediate devices (which power the transmitterelements) by means of a wireless connection, which can uselow-frequency, high-frequency or optical electromagnetic waves.

To avoid reducing the useful life of the power supply by overchargingthe power supply, the display units can preferably limit the rechargingcurrent, as soon as the voltage exceeds a specified threshold value.

If one or more display units are removed from the shelf for a ratherlong period of time which is longer than the discharge time of theinternal power source, the display units can preferably be stored in aseparate recharging station, in which they would receive an alternatingmagnetic field which is used to recharge their power supplies.

In summary, one aspect of the invention resides broadly in a system forthe electronic display of information on at least one shelf. The systemcomprises at least one display unit for displaying information. The atleast one display unit has an arrangement for disposing the at least onedisplay unit on a shelf arrangement. The at least one display unitcomprises at least one shelf display unit. The system further comprisesan arrangement for transmitting power to the at least one display unit,the transmitting arrangement for being disposed apart from the at leastone display unit. The at least one display unit comprises: anarrangement for receiving power from the transmitting arrangement; anarrangement for displaying information; and arrangement for powering thedisplaying arrangement at least partly from the power received by thereceiving arrangement. The receiving arrangement comprises anarrangement for receiving power from the transmitting arrangement solelyupon the at least one display unit being disposed substantially adjacentto at least a portion of the transmitting arrangement.

Another aspect of the invention also resides broadly in a system for theelectronic display of information on at least one shelf. The systemcomprises at least one display unit for displaying information, the atleast one display unit having an arrangement for disposing the at leastone display unit on a shelf arrangement. The at least one display unitcomprises at least one shelf display unit. The system further comprisesan arrangement for transmitting signals to the at least one display unitto provide data to the at least one display unit, the transmittingarrangement for being disposed apart from the at least one display unit.The at least one display unit comprises: an arrangement for receivingsignals from the transmitting arrangement; an arrangement for displayinginformation based on signals transmitted from the transmittingarrangement; and a rechargeable arrangement for powering the displayingarrangement. The transmitting arrangement comprises an arrangement forat least substantially continuously providing, to the receivingarrangement of the at least one display unit: data for the display ofinformation on the displaying arrangement; and power for providingenergy to the rechargeable arrangement.

Yet another aspect of the invention resides broadly in a method ofoperating a system for the electronic display of information on at leastone shelf. In this method, at least one display unit is provided fordisplaying information, the at least one display unit having anarrangement for disposing the at least one display unit on a shelfarrangement. The at least one display unit comprises at least one shelfdisplay unit. An arrangement is provided for transmitting power to theat least one display unit. The step of providing the at least onedisplay unit comprises: providing an arrangement for receiving powerfrom the transmitting arrangement; providing an arrangement fordisplaying information; and providing an arrangement for powering thedisplaying arrangement at least partly from the power received by thereceiving arrangement. The step of providing the receiving arrangementcomprises providing an arrangement for receiving power from thetransmitting arrangement solely upon the at least one display unit beingdisposed substantially adjacent to at least a portion of thetransmitting arrangement. The method further comprising the additionalsteps of: disposing the at least one display unit on a shelfarrangement; disposing the at least one display unit substantiallyadjacent to at least a portion of the transmitting arrangement;transmitting power to the at least one display unit with thetransmitting arrangement; receiving power, with the receivingarrangement, from the transmitting arrangement solely upon the at leastone display unit being disposed substantially adjacent to at least aportion of the transmitting arrangement; displaying information with thedisplaying arrangement; and powering the displaying arrangement at leastpartly from the power received by the receiving arrangement.

BRIEF DESCRIPTION OF THE DRAWINGS

Several embodiments of the invention are explained below in greaterdetail with reference to the accompanying drawings, which showschematically:

FIG. 1 a view of a system for electronically displaying prices,

FIG. 1a: an alternative embodiment of the system illustrated shown inFIG. 1,

FIG. 2: a cross section through a shelf equipped with a display unit,

FIG. 3: a view of a shelf equipped with a display unit,

FIG. 4: the inside of a display unit,

FIG. 5: a circuit to separate the recharging current from the datapackets,

FIG. 6: a curve which illustrates the frequency of the alternatingcurrent over time.

For a further understanding of at least one preferred embodiment of thepresent invention, and to show how the same may be carried into effect,reference will also be made, by way of example, to further drawings, inwhich:

FIGS. 7 to 16 show various embodiments of the invention in the form of adisplay unit mounted on a shelf edge moulding, both face-on and inperspective;

FIG. 17 shows a rear view of an empty display unit case, revealing a setof inductive coils;

FIG. 18 depicts the internal face of the back cover of a display unit,which cover comprises a charge foil laminate;

FIG. 19 shows a cut-away schematic of a preferred embodiment of adisplay unit in use; and

FIG. 20 shows the circuit layout of a charge circuit in FIG. 19.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The system for electronically displaying prices illustrated in FIG. 1can be used, for example, in a retail store. The shelves (1) arrangedabove and next to one another can be loaded with merchandise (5), theselling price of which merchandise can preferably be indicated byelectronic display units (4). The data displayed by the display devicesare preferably stored in a central computer (2) and are preferablyinductively transmitted by means of a control transmitter (3), andtransmitter elements (6) preferably laid on the edges of the shelves(1), to the display units (4) fastened in the immediate vicinity of thetransmitter elements (6). The control transmitter (3) and thetransmitter elements (6) can preferably be connected to one another bysupply leads (7). The drawing does not show that the control transmitter(3), in the pauses between the transmission of the individual datapackets, also preferably sends an alternating current through thetransmitter elements (6), which current preferably induces a voltageused to recharge the power source of the display units (4) (see,however, FIG. 6).

FIG. 1a is substantially the same view as FIG. 1, but illustrates analternative embodiment in accordance with the present invention.Particularly, as illustrated in FIG. 1a, it is conceivable to provide awireless connection between control transmitter (3) and transmitterelements (6), or even between computer (2) and control transmitter (3).Appropriate types of wireless connections in this vein, such as radiotransmission, electromagnetic transmission, and other types oftransmission, are generally well-known to those of ordinary skill in theart and will not be further described here. The general paths of thewireless connections in question are schematically indicated in FIG. 1aat (100) and (102).

FIG. 1a also illustrates an additional component contemplated by thepresent invention, namely recharging station (104). As illustrated,recharging station (104) can preferably be remote from the rest of thesystem and may essentially be configured for recharging individualdisplay units (4) in the event that such display units (4) are removedfrom the shelves (1). Accordingly, the recharging station (104) mayinclude an appropriately configured receptacle (106) for accommodatingone or more display unit or units (4) and recharging the correspondingpower supply or supplies of the display unit or units. The generalmakeup of such a recharging station (104) is considered to be wellwithin the purview of the skilled artisan and, as such, will not befurther discussed herein.

FIG. 2 shows that the display unit (4) can preferably be protectedinside a profile (8) fastened to the edge of the shelf (1). A leg (9) ofthe profile (8), which can preferably run diagonally upward, ispreferably in contact with the underside of the display unit (4), whilethe top of the display unit is preferably in contact with a second leg(10) of the profile (8), wherein the profile (8) itself preferably runsvertically downward. Preferably, the upper leg (10) is configured toimprove the legibility of the displays, so as to preferably shield thedisplays from the light which comes from above. The display unit (4) canpreferably be configured to move along the axis of the profile (8) andremoved therefrom (after loosening a fastening device, if such a deviceis present). Two transmitter elements (6) in the form of wirespreferably run on the reverse side of the display unit (4) on thesurface of the vertically-oriented part of the profile (8) in contactwith the display unit (4). The transmitter elements (6) are preferablyoriented parallel to the axis of the profile (8) and are preferablydisposed above one another. Preferably, the transmitter elements (6) arefastened to the profile (8), such as by means of a welded joint.

It should be appreciated that the profile (8) may alternatively beconsidered to be a "protective cover". Additionally, the second leg (10)may preferably be configured to run diagonally downward with respect tothe view shown in FIG. 2. The aforementioned "axis" of profile (8) maypreferably be considered to be parallel to the shelf edge in question.

FIG. 3 shows a front view of the profile (8) with a display unit (4). Asshown in FIG. 3, the display unit can preferably display a set of smallnumbers (11), which can preferably indicate product information, e.g.the product number, and a set of larger numbers (12) which canpreferably indicate the price. Alphanumeric displays can alsoconceivably be used instead of the numbers (11, 12). It should be notedthat it is possible to supply only one transmitter element (6) withcurrent, and to use the second as a backup unit in case of malfunctionor failure. On the other hand, if both transmitter elements (6) areoperated, currents can conceivably flow through them in the same oropposite directions.

FIG. 4 schematically illustrates the internal structure of a displayunit (4). Inside a housing (17), the electronic components arepreferably fastened to a printed circuit board (18). A component (13)for the inductive reception of the power emitted by the transmitterelements (6) is preferably a coil in the shape of a frame. This coil(13) preferably runs azimuthally on the inside wall of the housing (17),and is preferably connected to a rectifier circuit (16). The currentwhich occurs as a result of the induced voltages is preferably used tocharge a power supply (15), which, in the illustrated example is shownas a capacitor, and the power supply (15) preferably provides power fora microprocessor (14) and, strictly speaking, for the numerical displays(11, 12). The microprocessor (14) preferably updates the numbers (orletters) displayed if it receives a data packet specifically addressedto the display unit (4). In the illustrated embodiment, two transmitterelements (6) preferably run at some distance above and below the displayunit (4).

The aforementioned component (13) can conceivably be considered to be inthe shape of the housing (17).

FIG. 5 illustrates a rectifier and recharging circuit, of the type whichcan be used in the embodiment illustrated in FIG. 4. The alternatingcurrent induced in the component (13) used for reception, i.e. a coil,is preferably rectified by means of a diode (19) and reduced to thedesired operating voltage by a Zener diode (20). A Schottky diode (19')connecting the cathode of the Zener diode (20) to the power supply (15)(in this case a capacitor) preferably reduces the undesirable leakagecurrent of the Zener diode (20), and preferably recharges the capacitorto the operating voltage (24). The resistance (21) and the diodes (22)in inverse-parallel connection preferably limit the induced voltage to avoltage (23) appropriate to the input stage of the microprocessor (14).This circuit thereby makes it possible to use essentially only onecomponent (13) both to receive data packets and to recharge the powersupply (15).

FIG. 6 shows the curve of the frequency of the current which flowsthrough the transmitter element (6) as a function of time. During thephases of transmission of the data packets (25), a relatively lowfrequency is preferably frequency-modulated by a fraction (approximatelyone-fifth) of its amount, while the frequency in the pauses between thedata packets is preferably approximately doubled and remains constant.The display units (4) can thus easily distinguish between the twophases, on the basis of the frequency of the induced voltages.

It should be understood that the above examples of frequencies areessentially provided for the purposes of illustration and that othervariations in frequency can also be realized within the scope of thepresent invention.

It will be appreciated from the foregoing that the general result of thepresent invention is a system for indicating prices on shelves which ischaracterized by reliability and low maintenance costs.

It will also be appreciated from the foregoing that variations on thepreferred configurations discussed above are conceivable within thescope of the present invention. For example, for the purpose ofwirelessly transmitting energy to the different display units (6), it isconceivable to employ infrared, capacitive, electromagnetic, or opticalarrangements, as well as inductive arrangements. Optical arrangementscould conceivably include the use of lasers. For the power supply (15),it is conceivable to utilize, for example, a battery-type arrangement oreven a type of arrangement involving non-volatile memory. Additionally,for the transmission of data, it is conceivable to provide a constantalternating current with data superimposed thereupon.

The disclosure now turns to related embodiments of the presentinvention, as illustrated in FIGS. 7 through 20. It should be understoodthat various components discussed hereinbelow with relation to FIGS.7-20 can be considered to be interchangeable with components discussedfurther above with relation to FIGS. 1-6

Referring now to FIGS. 7 and 8, there is shown an electronic displayunit 1' mounted on a shelf edge profile 2'. The shelf edge profile 2'includes a single wire 3' which acts as a charge carrier.

Referring now to FIGS. 9 and 10, there is shown an electronic displayunit and a shelf edge profile as in FIGS. 7 and 8, but instead of asingle wire, there are provided two wires 4' which act as chargecarriers.

FIGS. 11 and 12 depict a similar arrangement to those shown in FIGS. 7to 10, except in that the shelf edge charge carriers comprise four wires5'.

FIGS. 13 and 14 depict an electronic display unit and a shelf edgeprofile wherein the shelf edge profile includes a flat ribbon 6' as acharge carrier.

FIGS. 15 and 16 show an arrangement substantially similar to thatdepicted in FIGS. 13 and 14, except in that two flat ribbons are used ascharge carriers.

Referring now to FIG. 17 there is shown a rear view of a display unitcase 8' which includes a set of inductive coils 9'. These inductivecoils 9' may receive and transmit data from and to a shelf edge chargecarrier or carriers 3', 4', 5', 6', 7' by means of electromagneticinductive coupling. The inductive coils 9' may also have electricalpower induced in them with which to power the display unit and/orrecharge an internal battery (not shown).

It will be appreciated that FIG. 17 may be considered to illustrate a"case with inductive coils enclosed".

FIG. 18 depicts the internal face of the back cover 10' of a particularembodiment of display unit. The back cover 10' includes a charge foillaminate 11'. The charge foil laminate 11' receives electrical powerfrom a shelf edge charge carrier or carriers by means of conductance orcharge coupling. This electrical power is then used to power the displayunit and/or to recharge an internal battery (not shown).

It will be appreciated that FIG. 18 may be considered to illustrate an"internal face of a back cover with charge foil laminate".

FIG. 19 shows a cut-away schematic of a preferred embodiment of displayunit in use. The shelf edge charge carriers 12', 13' are connected asoutlined above to a control transmitter unit (not shown) either directlyor via an intermediate slave and/or process controller (not shown). Thesystem may function satisfactorily with either charge carrier 12' or 13'operating independently by adjusting the coupling level to the displayunit 1' by varying either the number of display unit antenna coils 14'and/or the voltage applied to the shelf edge charge carriers. The RMSvoltage level on the charge carriers is typically 24 volts, but this maybe varied according to the distance between the display unit and thecharge carriers. The frequency of the alternating voltage on the chargecarriers is nominally the same as that used for the communication ofdata signals to the display unit and in this preferred embodiment mayvary between 36 kHz to 120 kHz. Coupling between the charge carriers 12'and/or 13' and the display unit 1' induces an alternating voltage in theantenna coils 14'. This alternating voltage then passes via chargecircuit 15' and support circuit 16' to microprocessor 17'. Price andother data transmission and reception may still occur at any time viathe support circuit 16'.

FIG. 20 shows the circuit layout of charge circuit 15' in FIG. 19. Thiscircuit contains two schottky diodes 18', 19" and a zener diode 20'. Thealternating current received from the antenna coil 14' is rectified bydiode 18' and clipped by zener diode 20' to the nominal battery voltage.Diode 19" serves to reduce the current leakage that would otherwiseoccur through zener diode 20'. The component set consisting of resistor21' and diodes 22', 23' serves to clip the input signal to the levelrequired by the preamplifier stage of the VLSI circuitry ofmicroprocessor 17'. Chargeable battery 24' has a nominal capacity of 3mAh or 7 mAh, and a potential of 3 volts. It is kept charged by theaction of charge circuit 15'.

It will be appreciated the FIGS. 19 and 20 may be considered toillustrate a "chargeable tag schematic layout and principle ofoperation".

One feature of the invention resides broadly in the system for theelectronic display of prices on shelves 1, with a computer 2, a controltransmitter 3 connected to it, and electronic display units 4 fastenedto the edges of the shelves 1, whereby at least the shelves 1 equippedwith display units 4 are provided with electrically conductingtransmitter elements 6, which are fed by the control transmitter 3 withan alternating current and emit electromagnetic energy, the controltransmitter 3 transmits to the display units 4, via the transmitterelements 6, data packets 25 which contain the data to be displayed, andwhich are separated from one another by pauses 26, and in each of thedisplay units 4 there is a component 13 to receive the energy emitted bythe transmitter elements 6 which feeds a charging current to arechargeable power supply 15 which supplies at least a portion of theoperating current of the display unit 4, characterized by the fact thatthe transmitter elements 6 are laid in the vicinity of the display units4 on the edges of the shelves 1, that the components 13 of the displayunits 4 inductively receive the energy emitted by the transmitterelements 6, and that the control transmitter 3 sends an alternatingcurrent to the transmitter elements 6 in the pauses 26 between the datapackets 25, and recharges the power supplies 15 of the display units 4.

Another feature of the invention resides broadly in the systemcharacterized by the fact that the display units 4 receive the datapackets 25 inductively.

Yet another feature of the invention resides broadly in the systemcharacterized by the fact that the power supply 15 is a capacitor and/ora storage battery.

Still another feature of the invention resides broadly in the systemcharacterized by the fact that the power sources 15 of the display units4 are also recharged during the transmission of the data packets 25.

A further feature of the invention resides broadly in the systemcharacterized by the fact that the display units 4, on the basis of theinduced voltages, switch between the recharging phase during which thepower source 15 is recharged and the phase during which a data packet 25is transmitted.

Another feature of the invention resides broadly in the systemcharacterized by the fact that the alternating current during the pauses26 between the data packets 25 is of constant frequency and/oramplitude.

Yet another feature of the invention resides broadly in the systemcharacterized by the fact that the control transmitter 3 modulatesand/or superimposes the data packets 25 on an alternating current ofconstant frequency and amplitude by amplitude modulation and/orfrequency modulation.

Still another feature of the invention resides broadly in the systemcharacterized by the fact that the frequency and/or amplitude of thealternating current during the transmission of the data packets 25differs from the frequency and/or amplitude during the pauses 26.

A further feature of the invention resides broadly in the systemcharacterized by the fact that the display units 4, after the receptionof a data packet 25, for their part emit a data packet which istransmitted inductively to the adjacent transmitter element 6 and fromthe latter via the control transmitter 3 to the computer 2.

Another feature of the invention resides broadly in the systemcharacterized by the fact that the display units 4 have a component 13used to transmit both energy and data.

Yet another feature of the invention resides broadly in the systemcharacterized by the fact that the display units 4 are equipped with twoseparate components 13, one of which is used for energy transmission andone for data transmission.

Still another feature of the invention resides broadly in the systemcharacterized by the fact that the component 13 is a flat coil wound inlayers.

A further feature of the invention resides broadly in the systemcharacterized by the fact that the transmitter elements 6 aresingle-conductor or multiple-conductor cables.

Another feature of the invention resides broadly in the systemcharacterized by the fact that the transmitter elements 6 are flatribbon cables.

Yet another feature of the invention resides broadly in the systemcharacterized by the fact that the transmitter elements 6 are moldedinto a profile 8 which forms the edge of the shelf 1.

Still another feature of the invention resides broadly in the systemcharacterized by the fact that at least the parts of the transmitterelements 6 adjacent to the display units 4 are laid in the form ofloops.

A further feature of the invention resides broadly in the systemcharacterized by the fact that the Control transmitter 3 is hard-wiredto the transmitter elements 6.

Another feature of the invention resides broadly in the systemcharacterized by a wireless connection between the computer 1 and thecontrol transmitter 3 and/or between the control transmitter 3 and thetransmitter elements 6.

Yet another feature of the invention resides broadly in the systemcharacterized by the fact that the display units 4 limit the rechargingcurrent of their power supply 15, as soon as the voltage of the powersupply 15 exceeds a specified threshold.

Still another feature of the invention resides broadly in the systemcharacterized by a recharging station for separate display units 4 whichhave been removed from the shelves.

It will be appreciated from the foregoing that the present invention,may, in at least one preferred embodiment thereof, preferably relate toan electronic shelf edge display system, and in particular, to a shelfedge display system which incorporates display units which receiveelectrical power by means of wireless coupling.

In the field of modern retailing, the increasing use of bar codes toidentify the nature and the price of products has resulted in thediminished use of individual price tags or stickers on each item ofmerchandise. In order to indicate the price of an item, a tag or labelis applied to the edge of the shelf on which the item is located.However, there is no guarantee that the price on the label is the sameas the price held in the store computer, and this can lead to customercomplaints and possible legal action against the retailer. Updating suchshelf edge labels is also very inefficient, as each label has to bereprinted and replaced manually. Accordingly, electronic shelf edgedisplay tags have been developed, which display price and otherinformation relating to the items of merchandise. As these display tagsare linked to the store computer, it is ensured that the price displayedon a tag is the price which will be charged at the checkout.Furthermore, it is a simple matter to update the information on anyparticular display tag from the central computer by means of atransmission comprising an address code unique to each tag or group oftags and price data relating to the product associated with the tag orgroup of tags. This enables price changes, for instance promotionalprice decreases, to be effected with minimum fuss.

Certain such electronic display systems, such as that disclosed in U.S.Pat. No. 4,500,880 (Gomersall), comprise display tags which arephysically connected to the store computer and a power source by meansof conductive wires. These systems have the disadvantage that thehard-wired connection is cumbersome if tags are to be frequently moved.Furthermore, the contacts between the display tags and the connectingwires are subject to wear and tear, which soon results in unreliabledata and/or power transmission to the tags.

Other types of electronic display system, such as that disclosed in U.S.Pat. No. 4,888,709 (Revesz), comprise independent display tags poweredby internal batteries. Information is transmitted to these tags from thestore computer by means of infra-red or radio transmitters, which aregenerally mounted in the ceiling of the store. These systems have theadvantage that the display tags may be moved freely from place to placewithin the store. However, systems of this type still require checkingto ensure that the individual batteries in each tag have not run down.Furthermore, the use of infra-red or radio transmissions over arelatively large distance, i.e. of the order of meters, can result ininterference and/or signal shielding. This is because radiotransmissions have a wavelength of the same order of magnitude as thedimensions of the store, and may therefore set up standing waves withresultant interference. Infra-red radiation does not penetrate solidobjects very easily, and an infra-red transmission may therefore beinadvertently prevented from reaching a display unit.

Due to the shortcomings of presently available systems, as describedabove, there is a need for an electronic display system with theflexibility afforded by individual display units which are nothard-wired to the store computer or power source, and also thereliability of a separate power source other than internal batteries.Data transmission which is not subject to interference, shielding orfaulty connection to the store computer is also required. Accordingly,we have developed a system which comprises one or more electronicdisplay units adapted to be mounted on shelf edges, which shelf edgesinclude at least one continuous charge carrier which is in communicationwith a central computer via one or more control transmitters, whereinsaid one or more display units each comprise an element with which saidcharge carrier forms a wireless link, the wireless link enabling thetransmission of electrical power to said one or more display units.

The at least one charge carrier included in the shelf edge may comprisea single or multiple core cable, a loop or loops, or a flat ribbon orribbons which may be moulded into the shelf edge profile material duringmanufacture or bonded onto the shelf edge profile material before orafter installation or mounted separately on the shelf edge.

The element in the display unit with which the charge carrier forms awireless link may consist of an inductive coil or coils, or a chargefoil laminate.

The separation between the element in a display unit and thecorresponding charge carrier included in the shelf edge will generallybe constrained by the maximum depth of the particular shelf edgeprofile, typically in the range of 5 to 25 mm.

Electrical power is transmitted to the display unit by means of wirelessinductive coupling or by wireless charge coupling or by wirelesscapacitance coupling between the shelf edge charge carrier or carriersand the element in the display unit.

Price data, address data and other information is preferably transmittedto a display tag by means of wireless coupling, which will generally beinductive coupling, between the charge carrying element included in theshelf edge and the element included in the display unit. The displayunit may transmit data such as confirmation data back to the shelf edgecharge carrier by means of similar wireless coupling. FIG. 4schematically illustrates a return transmitting arrangement 200 whichmay be provided for this purpose. Suitable arrangements for this purposewill be well-known to those of ordinary skill in the art and will thisnot be described in any further detail herein.

In one embodiment of this invention, when data communication between theshelf edge charge carrier and the display tag is not active, thetransmitter transmits a steady state alternating low voltage current inthe shelf edge charge carrier, which current gives rise to analternating low voltage current in the element included in the displayunit. This current is used to charge a rechargeable battery, and/or acapacitor or other chargeable/dischargeable power source. In thisembodiment, means are provided for switching between data transmissionand the low voltage charging current within the control transmitterunit, and also for discrimination between data transmission and chargingstate in the display unit.

In a second embodiment of this invention, a continuous alternatingvoltage threshold is maintained in the shelf edge charge carriers forproviding charging power to the display unit, and price data, addressdata and other information is transmitted by means of signals superposedon the continuous alternating voltage.

In a further embodiment of this invention, a continuous alternatingvoltage threshold is maintained in the shelf edge charge carriers forenergy provision within the display units by means of coupling with areciprocal charge carrying element within the display unit and therebygiving rise to sufficient electrical energy to power directly any or allof the memory, data processing, data display or data transmissionfunctions included in the display unit. Price data, address data andother information is transmitted by means of signals superposed on thecontinuous alternating voltage.

The data for transmission to, and display on, the shelf edge units maybe held in a central computer at, for example, the head office of aretailing chain, and be transmitted to individual store computers viatelephone links or any other suitable means. Alternatively, the headoffice computer is omitted and the data is held in the individual storecomputers. It will be understood that the term "computer" is intended tocover any electronic data storage and processing device, for exampleEPOS (Electronic Point-Of-Sale) price file controllers and the like.

Data is transmitted to the display units from any combination of theabove computer arrangements via one or more control transmitter units.These control transmitter units may be hard-wired to the shelf edgecharge carrying elements, or they may transmit to intermediate gondola-or otherwise-mounted slave and/or process controllers by means of awireless link which may comprise low, high, very high or ultra highfrequency electromagnetic radiation. The intermediate slave and/orprocess controllers transmit the received data to the display units bymeans of the shelf edge charge carrier or carriers.

The display units are advantageously adapted so as to transmit data suchas confirmation data back to the store computer or headquarters computerby means of wireless coupling with the shelf edge charge carriers andthence via the various intermediate units and control transmitters.

Preferred embodiments of the invention may offer the followingadvantages over known systems:

i) a short distance, very low power wireless radio frequency linkbetween the display units and the control system, which wireless link ishighly resistant to interference and allows secure two-way datacommunication; and

ii) an independently powered tag that can be removed from a shelf edgewithout loss of memory for a pre-determined period of time, typically upto a number of weeks; and

iii) a low cost, variable capacity internal power source of indefinitelife.

In the event that one or more display units are to be removed from theshelf edge for a time longer than the discharge time of the internalpower source, the display units may be stored in a remote storage box inwhich charging may occur so as to maintain their memory states untilthey are put back on the shelf edge.

Examples of circuit boards, which may be utilized in accordance with theembodiments of the present invention, may be found in the following U.S.Pat. No. 5,303,466, which issued to Ozai et al. on Apr. 19, 1994; U.S.Pat. No. 5,304,252, which issued to Condra et al. on Apr. 19, 1994; andU.S. Pat. No. 5,304,428, which issued to Takami on Apr. 19, 1994.

Examples of microprocessors having addressing capabilities, which may beutilized in accordance with the embodiments of the present invention,may be found in the following U.S. Pat. No. 4,541,045, which issued toKromer on Sep. 10, 1985; U.S. Pat. No. 4,419,727, which issued to Holteyet al. on Dec. 6, 1983; U.S. Pat. No. 4,307,448, which issued to Sattleron Dec. 22, 1981; and U.S. Pat. No. 4,202,035, which issued to Lane onMay 6, 1980.

Examples of Schottky diodes, which may be utilized in accordance withthe embodiments of the present invention, may be found in the followingU.S. Pat. No. 5,304,944, which issued to Copeland et al. on Apr. 19,1994; U.S. Pat. No. 5,302,956, which issued to Asbury et al. on Apr. 12,1994; and U.S. Pat. No. 5,301,048, which issued to Huisman on Apr. 5,1994.

Examples of Zener diodes, which may be utilized in accordance with theembodiments of the present invention, may be found in the following U.S.Pat. No. 5,305,176, which issued to Hirota on Apr. 19, 1994; U.S. Pat.No. 5,276,350, which issued to Merrill et al. on Jan. 4, 1994; and U.S.Pat. No. 5,252,908, which issued to Brokaw on Oct. 12, 1993.

Examples of non-volatile memory arrangements, which may be utilized inaccordance with the embodiments of the present invention, may be foundin the following U.S. Pat. No. 5,301,161, which issued to Landgraf etal. on Apr. 5, 1994; U.S. Pat. No. 5,292,681, which issued to Lee et al.on Mar. 8, 1994; and U.S. Pat. No. 5,293,062, which issued to Nakao onMar. 8, 1994.

Examples of other components, such as transmission arrangements, wiringarrangements, and computer arrangements, which may conceivably beutilized in accordance with the embodiments of the present invention,may be found in the following U.S. Pat. No. 4,888,709, which issued toRevesz; U.S. Pat. No. 4,821,921, which issued to Stevens et al. on Apr.11, 1989; U.S. Pat. No. 4,521,677, which issued to Sarwin in Jun. 1985;U.S. Pat. No. 4,500,880, which issued to Gomersall et al. in Feb. 1985;U.S. Pat. No. 4,339,772, which issued to Eilers et al. in Jan. 1982; andU.S. Pat. No. 4,028,537, which issued to Snow in June 1977.

The appended drawings in their entirety, including all dimensions,proportions and/or shapes in at least one embodiment of the invention,are accurate and to scale and are hereby included by reference into thisspecification.

All, or substantially all, of the components and methods of the variousembodiments may be used with at least one embodiment or all of theembodiments, if any, described herein.

All of the patents, patent applications and publications recited herein,and in the Declaration attached hereto, are hereby incorporated byreference as if set forth in their entirety herein.

The corresponding foreign patent publication applications, namely,British Patent Application No. 9309246.8, filed on May 5, 1993, havinginventors Chris Escritt and Magnus Hellquist, and British Laid OpenPatent Application No. 9309246.8 and British Patent No. 9309246.8, aswell as their published equivalents, and other equivalents orcorresponding applications, if any, in corresponding cases in the UnitedKingdom, the Federal Republic of Germany and elsewhere, and thereferences cited in any of the documents cited herein, are herebyincorporated by reference as if set forth in their entirety herein.

The details in the patents, patent applications and publications may beconsidered to be incorporable, at applicant's option, into the claimsduring prosecution as further limitations in the claims to patentablydistinguish any amended claims from any applied prior art.

The invention as described hereinabove in the context of the preferredembodiments is not to be taken as limited to all of the provided detailsthereof, since modifications and variations thereof may be made withoutdeparting from the spirit and scope of the invention.

What is claimed is:
 1. System for the electronic display of informationon at least one shelf, said system comprising:a plurality of displayunite for displaying information, each of said plurality of displayunits comprising at least one shelf display unit; means for transmittingpower to said plurality of display units; said transmitting means forbeing disposed apart from said plurality of display units; each of saidplurality of display units comprising:means for receiving power fromsaid transmitting means; means for displaying information; and means forpowering said displaying means at least partly from the power receivedby said receiving means; said receiving means comprising means forreceiving power from said transmitting means solely upon said displayunit being disposed substantially adjacent to at least a portion of saidtransmitting means; said transmitting means comprising a transmitter forat least transmitting power; said at least a portion of saidtransmitting means comprising at least one transmitter element, said atleast one transmitter element being electrically conductive and beingconfigured to receive power from said transmitter; at least one of saidplurality of display units having means for disposing said at least onedisplay unit on a shelf; said receiving means of said at least one ofsaid plurality of display units comprising means for receiving powerfrom said transmitting means solely upon said display unit beingdisposed substantially adjacent to, and substantially on the same shelfas, said at least one of said at least one transmitter element; saidmeans for powering said displaying means comprising rechargeable meansfor powering said displaying means; said transmitting means comprisingmeans for at least substantially continuously providing, to saidreceiving means of said at least one display unit:data for the displayof information on said displaying means; and power for providing energyto said rechargeable means; said means for at least substantiallycontinuously providing data and power to said at least one display unitcomprising:means for transmitting data to said at least one display unitin the form of intermittently transmitted data packets, the intermittenttransmissions of data packets for being interrupted by pauses; end meansfor transmitting power; said means for transmitting power comprisingmeans for transmitting power to said at least one display unit duringthe pauses between the intermittent transmissions of data packets; saidreceiving means comprising means for receiving power from saidtransmitting means during the pauses between intermittent transmissionsof data packets; and said means for transmitting power during the pausesbetween the intermittent transmissions of data packets comprising meansfor transmitting power to said at least one display unit to rechargesaid rechargeable means during the pauses between the intermittenttransmissions of data packets.
 2. The system according to claim 1,wherein said transmitting means is configured such that each data packetis transmitted over a period of time having an order of magnitude ofsubstantially less than one second.
 3. The system according to claim 2,wherein said means for transmitting power comprises means fortransmitting power to said at least one display unit during pausesbetween consecutive intermittent transmissions of single data packets.4. The system according to claim 3, wherein said receiving meanscomprises a single circuit for receiving both power and data from saidtransmitting means.
 5. The system according to claim 4, wherein:saidreceiving means of said at least one of said at least one display unitis configured for inductively receiving energy emitted by said at leastone transmitter element; said transmitter is configured for sending analternating current to said at least one transmitter element at leastbetween the intermittent transmissions of data packets; said receivingmeans of said at least one of said at least one display unit isconfigured for inductively receiving the intermittent transmissions ofdata packets; said means for transmitting power at least between theintermittent transmissions of data packets comprises means fortransmitting power to said at least one display unit both between theintermittent transmissions of data packets and during the intermittenttransmissions of data packets; said at least one of said at least onedisplay unit comprises means for switching between:a phase, during whichsaid rechargeable power supply means is recharged; and a phase, duringwhich a data packet is transmitted; said transmitter is configured suchthat:the data packets are incorporated with an alternating current ofconstant frequency and amplitude by way of frequency modulation; and atleast one parameter of the alternating current is different duringtransmissions of the data packets than between transmissions of the datapackets; said at least one of said at least one display unit comprisesmeans for emitting an additional data packet upon receipt of a datapacket; said means for emitting comprises means for inductivelytransmitting the additional data packet to one of said at least onetransmitting element; said system further comprises a computer fortransmitting data to said transmitter; said one of said at least onetransmitting element comprises means for transmitting the additionaldata packet to said transmitter and subsequently to said computer; saidreceiving means comprises at least one component configured forproviding both data and power to said displaying means; said receivingmeans comprises at least one coil, said at least one coil comprising aflat coil being wound in layers; said at least one transmitting elementcomprises at least one cable; said at least one transmitting elementcomprises means for being molded into a profile forming a shelf edge;said at least one transmitting element is configured for being disposedin a loop, along at least one shelf edge; said at least one display unitcomprises a plurality of display units; said at least one transmittingelement is configured for being disposed substantially adjacent to aplurality of said plurality of display units; said transmitter isconfigured for transmitting to said at least one transmitting element byat least one hard-wired connection; said computer is configured fortransmitting to said transmitter by at least one hard-wired connectionsaid at least one display unit is configured for limiting the rechargingcurrent of said rechargeable power supply means as soon as the voltageof said rechargeable power supply means exceeds a specified threshold;said at least one transmitting element comprises a plurality oftransmitting elements, each of said plurality of transmitting elementsfor being disposed on e different, corresponding shelf; and said systemfurther comprises a recharging station for recharging at least onedisplay unit which has been removed from a shelf.
 6. System for theelectronic display of information on at least one shelf, said systemcomprising:a plurality of display units for displaying information, eachof said plurality of display units comprising at least one shelf displayunit; means for transmitting signals to said plurality of display unitsto provide data to said plurality of display units; said transmittingmeans for being disposed apart from said plurality of display units;each of said plurality of display units comprising:means for receivingsignals from said transmitting means; means for displaying informationbased on signals received by said receiving means; and rechargeablemeans for powering said displaying means; said transmitting meanscomprising means for et least substantially continuously providing, tosaid receiving means of at least one of said at least one displayunit:data providing for the display of information on said displayingmeans; and power for providing energy to said rechargeable means; saidmeans for at least substantially continuously providing data and powerto said at least one display unit comprising means for transmitting datato said at least one display unit in the form of intermittentlytransmitted data packets, the intermittent transmissions of data packetsfor being interrupted by pauses; said means for et least substantiallycontinuously providing data and power to said at least one display unitcomprising means for transmitting power to said at least one displayunit during the pauses between the intermittent transmissions of datapackets; and said receiving means comprising means for receiving powerfrom said transmitting means during the pauses between intermittenttransmissions of data packets.
 7. The system according to claim 6,wherein said transmitting means is configured such that each data packetis transmitted over a period of time having an order of magnitude ofsubstantially less than one second.
 8. The system according to claim 7,wherein said means for transmitting power comprises means fortransmitting power to said at least one display unit during pausesbetween consecutive intermittent transmissions of single data packets.9. The system according to claim 8, wherein said receiving meanscomprises a single circuit for receiving both power and data from saidtransmitting means.
 10. The system according to claim 9, wherein:saidmeans for transmitting power at least between the intermittenttransmissions of data packets comprises means for transmitting power tosaid at least one display unit to recharge said rechargeable means atleast between the intermittent transmissions of data packets.
 11. Thesystem according to claim 10, wherein:said receiving means comprisesmeans for receiving power from said transmitting means solely upon saiddisplay unit being disposed substantially adjacent to at least a portionof said transmitting means.
 12. The system according to claim 11,wherein:said transmitting means comprises a transmitter for at leasttransmitting power; said at least a portion of said transmitting meanscomprises at least one transmitter element, said at least onetransmitter element being electrically conductive and being configuredto receive power from said transmitter; at least one of said at leastone display unit has means for disposing said at least one of said atleast one display unit on a shelf; said means for disposing said atleast one of said at least one display unit on a shelf comprises meansfor disposing said at least one of said at least one display unitsubstantially at an edge of a shelf; said receiving means of said atleast one of said at least one display unit comprises means forreceiving power from said transmitting means solely upon said at leastone of said at least one display unit being disposed substantiallyadjacent to, and substantially at the same shelf edge as, said at leastone of said at least one transmitter element; and said receiving meansof said at least one of said at least one display unit comprises meansfor receiving data from said transmitting means solely upon said atleast one of said at least one display unit being disposed substantiallyadjacent to, and substantially at the same shelf edge as, said at leastone of said at least one transmitter element.
 13. The system accordingto claim 12, wherein:said receiving means of said at least one of saidat least one display unit is configured for inductively receiving energyemitted by said at least one transmitter element; said transmitter isconfigured for sending an alternating current to said at least onetransmitter element at least between the intermittent transmissions ofdata packets; said receiving means of said at least one of said at leastone display unit is configured for inductively receiving theintermittent transmissions of data packets; said means for transmittingpower at least between the intermittent transmissions of data packetscomprises means for transmitting power to said at least one display unitboth between the intermittent transmissions of data packets and duringthe intermittent transmissions of data packets; said at least one ofsaid at least one display unit comprises means for switching between:aphase, during which said rechargeable power supply means is recharged;and a phase, during which a data packet is transmitted; said transmitteris configured such that:the data packets are incorporated with analternating current of constant frequency and amplitude by way offrequency modulation; and at least one parameter of the alternatingcurrent is different during transmission of the data packets thanbetween transmissions of the data packets; said at least one of said atleast one display unit comprises means for emitting an additional datapacket upon receipt of a data packet; said means for emitting comprisesmeans for inductively transmitting the additional data packet to one ofsaid at least one transmitting element; said system further comprises acomputer for transmitting data to said transmitter; said one of said atleast one transmitting element comprises means for transmitting theadditional data packet to said transmitter and subsequently to saidcomputer; said receiving means comprises at least one componentconfigured for providing both data and power to said displaying means;said receiving means comprises at least one coil, said at least one coilcomprising a flat coil being wound in layers; said at least onetransmitting element comprises at least one cable; said at least onetransmitting element comprises means for being molded into a profileforming a shelf edge; said at least one transmitting element isconfigured for being disposed in a loop, along at least one shelf edge;said at least one display unit comprises a plurality of display units;said at least one transmitting element is configured for being disposedsubstantially adjacent to a plurality of said plurality of displayunits; said transmitter is configured for transmitting to said at leastone transmitting element by at least one hard-wired connection; said atleast one display unit is configured for limiting the recharging currentof said rechargeable power supply means as soon as the voltage of saidrechargeable power supply means exceeds a specified threshold; said atleast one transmitting element comprises a plurality of transmittingelements, each of said plurality of transmitting elements for beingdisposed on a different, corresponding shelf; and said system furthercomprises a recharging station for recharging at least one display unitwhich has been removed from a shelf.
 14. Method of operating a systemfor the electronic display of information on at least one shelf, saidmethod comprising the steps of:providing a plurality of display unitsfor displaying information, each of the plurality of display unitscomprising at least one shelf display unit; providing means fortransmitting power to said plurality of display units; said step ofproviding the plurality of display units comprising:providing means forreceiving power from the transmitting means; providing means fordisplaying information; and providing means for powering the displayingmeans at least partly from the power received by the receiving means;and said step of providing the receiving means comprising providingmeans for receiving power from the transmitting means solely upon thedisplay unit being disposed substantially adjacent to at least a portionof the transmitting means; said method further comprising the additionalsteps of:disposing the display units on shelf means; disposing thedisplay units substantially adjacent to at least a portion of thetransmitting means; transmitting power to the display units with thetransmitting means; receiving power, with the receiving means, from thetransmitting means solely upon the display units being disposedsubstantially adjacent to at least a portion of the transmitting means;displaying information with the displaying means; powering thedisplaying means at least partly from the power received by thereceiving means; said step of providing the transmitting meanscomprising:providing a transmitter for at least transmitting power;configuring the at least a portion of the transmitting means to compriseat least one transmitter element, the at least one transmitter elementbeing electrically conductive and being configured to receive power fromthe transmitter; configuring at least one display unit to have means fordisposing the at least one display unit on a shelf; configuring thereceiving means of the at least one of the display unit to comprisemeans for receiving power from the transmitting means solely upon the atleast one display unit being disposed substantially adjacent to, andsubstantially on the same shelf as, the at least one transmitterelement; said method further comprises the steps of:disposing the atleast one display unit on a shelf substantially at an edge of the shelf;receiving power from the transmitting means, with the receiving means,solely upon the at least one display unit being disposed substantiallyadjacent to, and substantially at the same shelf edge as, the at leastone of the at least one transmitter element; transmitting data to the atleast one display unit with the transmitting means; displayinginformation, with the means for displaying information, based on datatransmitted from the transmitting means; wherein the receiving meansreceives data from the transmitting means solely upon the at least oneof the at least one display unit being disposed substantially adjacentto, and substantially at the same shelf edge as, the at least onetransmitter element; wherein the means for powering the displaying meanscomprises rechargeable means for powering the displaying means; whereinthe transmitting means substantially continuously provides, to thereceiving means of the at least one display unit:data for the display ofinformation on the displaying means; and power for providing energy tothe rechargeable means; wherein the at least substantially continuousprovision of data and power to the at least one display unitcomprises:transmitting data to the at least one display unit in the formof intermittently transmitted data packets, and interrupting theintermittent transmissions of data packets with pauses; and transmittingpower to the at least one display unit at the pauses between theintermittent transmissions of data packets; wherein power is transmittedto the at least one display unit to recharge the rechargeable meansduring the pauses between intermittent transmissions of data packets;and the receiving means receives power from the transmitting meansduring the pauses between consecutive intermittent transmissions of datapackets.
 15. The method according to claim 14, wherein each date packetis transmitted, by the transmitting means, over e period of time havingan order of magnitude of substantially less than one second.
 16. Thesystem according to claim 15, wherein power is transmitted, by thetransmitting means, to said at least one display unit during pausesbetween consecutive intermittent transmissions of single data packets.17. The system according to claim 16, wherein the receiving meanscomprises a single circuit for receiving both power and data from saidtransmitting means.
 18. The method according to claim 17, furthercomprising the step of configuring the system such that:the receivingmeans of the at least one of the at least one display unit is configuredfor inductively receiving energy emitted by the at least one transmitterelement; the transmitter is configured for sending an alternatingcurrent to the at least one transmitter element at least between theintermittent transmissions of data packets; the receiving means of theat least one of the at least one display unit is configured forinductively receiving the intermittent transmissions of data packets;the means for transmitting power at least between the intermittenttransmissions of data packets comprises means for transmitting power tothe at least one display unit both between the intermittenttransmissions of data packets and during the intermittent transmissionsof data packets; the at least one of the at least one display unitcomprises means for switching between:a phase, during which therechargeable power supply means is recharged; and a phase, during whicha data packet is transmitted; the transmitter is configured suchthat:the data packets are incorporated with an alternating current ofconstant frequency and amplitude by way of frequency modulation; and atleast one parameter of the alternating current is different duringtransmission of the data packets than between transmissions of the datapackets; the at least one of the at least one display unit comprisesmeans for emitting an additional data packet upon receipt of a datapacket; the means for emitting comprises means for inductivelytransmitting the additional data packet to one of the at least onetransmitting element; the system further comprises a computer fortransmitting data to the transmitter; the one of the at least onetransmitting element comprises means for transmitting the additionaldata packet to the transmitter and subsequently to the computer; thereceiving means comprises at least one component configured forproviding both data and power to the displaying means; the receivingmeans comprises at least one coil, the at least one coil comprising aflat coil being wound in layers; the at least one transmitting elementcomprises at least one cable; the at least one transmitting elementcomprises means for being molded into a profile forming a shelf edge;the at least one transmitting element is configured for being disposedin a loop, along at least one shelf edge; the at least one display unitcomprises a plurality of display units; the at least one transmittingelement is configured for being disposed substantially adjacent to aplurality of the plurality of display units; the transmitter isconfigured for transmitting to the at least one transmitting element byat least one wireless connection; the at least one display unit isconfigured for limiting the recharging current of the rechargeable powersupply means as soon as the voltage of the rechargeable power supplymeans exceeds a specified threshold; the at least one transmittingelement comprises a plurality of transmitting elements, each of theplurality of transmitting elements for being disposed on a different,corresponding shelf; and the system further comprises a rechargingstation for recharging at least one display unit which has been removedfrom a shelf.
 19. The system according to claim 18, wherein therechargeable power supply means comprises a capacitor.
 20. The methodaccording to claim 18, wherein the rechargeable power supply meanscomprises a storage battery.